Stripping mechanisms are utilized in folders of printing presses to push or strip signatures out of rotating buckets such that the signatures are deposited onto a conveyor. Stripping mechanisms generally include a plurality of individual strippers.
A bucket assembly typically includes a plurality of buckets rotating on a common bucket shaft. The buckets are spaced axially along the shaft. The strippers are designed to reach between the rotating buckets. When a signature enters a bucket assembly and is stripped from the buckets, it touches all buckets and all strippers along its width. In folders having buckets that are adjustable to accommodate varying widths of signatures, the stripping mechanism also needs to be adjustable. The stripping mechanism should be adjustable to locate the stripping surface of each of the strippers similarly and at ideally the best angle and best location relative to the rotating path of the signatures as the signatures turn in the rotating buckets. For example, a specific job may require four buckets with three strippers placed therebetween. The goal of adjusting the three strippers is to set each stripper at the same location and same angle as each of the other strippers so they are aligned. This is typically difficult to accomplish because each stripper has its own individual adjustments.
Some prior art stripping mechanisms are adjustable using an arrangement that controls more than one degree of freedom of movement of an individual stripper with respect to a shaft; e.g., both axial sliding and rotating. Due to the two degrees of freedom of movement in such an arrangement, the adjustment can be difficult to perform. For example, if an operator only wants to slide the individual stripper axially along the shaft, when a handle is loosened, the stripper may also inadvertently rotate about its shaft. Having too many degrees of freedom in a stripper adjustment can make an individual adjustment more difficult to perform.
Another problem that exists with some stripping mechanisms relates to how far the adjustment mechanism sticks out towards the next adjacent stripper. It is desirable to have buckets that are close together and strippers that reach between the buckets because these conditions make for better high-speed signature handling in the folder. However, if an adjustment handle sticks out too far towards the adjacent stripper, it becomes awkward and/or impossible to adjust the bucket assembly and the adjacent strippers because there is not enough room between the buckets for a press operator to adjust each stripper.
Additionally, some stripping mechanisms are only adjustable when the folder is stopped, or the adjustments are more difficult and dangerous to make while the folder is running. The ideal time to adjust the strippers is while the folder is running because the operator can see what effect the adjustment has on how the signatures are being stripped from the buckets. Adjusting the stripping mechanism while the folder is running provides immediate feedback on whether the adjustment is improving how the signatures are being stripped.
Before the press operator starts adjusting the stripping mechanism, the operator must have knowledge of the best location and the best angle of the strippers so that the folder can run at its fastest speed without damaging the signatures that are being processed and stripped from the buckets. Strippers can damage signatures running at high speeds if the strippers are adjusted to the wrong location or to the wrong angle. Proper positioning of the strippers typically requires much press experience and knowledge. For example, if an inexperienced press operator adjusts the strippers to a location and angle that is less than optimum, this slows down the processing speed of the signatures and/or may damage the signatures.
Further, it is desirable that installation or removal of the stripping mechanism from the folder be easy and fast to perform. Often, this installation or removal is a slow, difficult process. When the folder is not running, profits on the production line which includes the printing press, folder, stackers, and press personnel are lost. Therefore, the goal is to keep the down time of the press to a minimum, and to set the folder up, including installing or removing the stripping mechanism, as quickly as possible for different signature width jobs.